Protoceratopsid

Skeletal reconstruction of Protoceratops

• East Asia

The Protoceratopsidae (also Protoceratopidae ) are a taxon ( a systematic group) of the dinosaurs from the group of ceratopsians. They include, according to current view Protoceratops and Bagaceratops as well as some little-known, controversial genres.

Features

The Protoceratopsidae were relatively small dinosaur, Protoceratops reached up to two meters in length, Bagaceratops only about half. ( The controversial Udanoceratops other hand reached up to 4 meters. ) As with all Ceratopsia the snout from the Rostralknochen and the Praedentale was formed. Characteristics of this group represent among other things a little horn on the nose leg and changes of the mandible - about a pointed front end of the Praedentale - represents the teeth were aligned, as with all Ceratopsia on a plant-based diet, in contrast to the dental batteries Ceratopsidae they were but simply built.

Outer systematics and evolution

All finds of Protoceratopsidae come from East Asia (Mongolia and China ) and are dated to the Upper Cretaceous ( Santonian or Campanian ) at a age of 85 million to 70 million years. They are incorporated within the Ceratopsia in the Neoceratopsia. A possible cladogram is as follows.

Protoceratopsidae

Leptoceratopsidae

Ceratopsoidea ( Zuniceratops and Ceratopsidae )

Basal Neoceratopsia ( archaeoceratops and others)

Other studies, however, see the Leptoceratopsidae as basal representatives of Coronosauria and the related Protoceratopsidae as being closer to the Ceratopsoidea.

Inside systematics

The Protoceratopsidae were minted in 1923 by Walter Granger and William King Gregory, first as a monotypic family for Protoceratops. Later, the group served as a gathering point for all ceratopsians, the more highly developed than the Psittacosauridae, but were basal than the Ceratopsidae. This group has been found to be paraphyletic, so today, among other things, the predominantly North American Leptoceratopsidae be considered as a separate family.

A possible species list looks like this:

• Bagaceratops
• Bainoceratops
• Breviceratops
• Graciliceratops
• Lamaceratops
• Magnirostris
• Platyceratops
• Protoceratops
• Udanoceratops

Protoceratops and Bagaceratops are closely related and form a monophyletic group according to various analyzes. Graciliceratops was also attributed to the Protoceratopsidae at its first description in 2000 as magnirostris 2003. Also in 2003, described Alifanov with Lamaceratops and Platyceratops two new dinosaurs, which he filed with Bagaceratops and Breviceratops in a new family, Bagaceratopsidae.

On the validity of Breviceratops there were already more uncertainties, it could merely be a young animal of Bagaceratops. Makovicky and Norell presented next to 2006, the validity of Lamaceratops, magnirostris and Platyceratops in question, in their opinion, it could also be synonyms of Bagaceratops.

The membership of Udanoceratops is controversial. It shows the construction of the lower jaw similarities with the Leptoceratopsidae and is sometimes attributed to this group. Bainoceratops likely to be closely related to Udanoceratops and how these have to be classified.

In summary, a close relationship and monophyly of the two better-known genera Protoceratops and Bagaceratops largely, while the remaining, poorly preserved, findings are controversial not in doubt.